"So, I think we do need to make sure that there's some conditionality between the two."

He added: "Certainly it needs to go into the arrangements we have at international level with our EU partners.

"We need to make it clear that the two are linked."

Mr Raab has accused the EU of "irresponsibly" ramping-up pressure in withdrawal negotiations.

Asked about comments from Brussels that a no-deal scenario would mean there would be no specific arrangements in place for UK citizens living on the continent, or for EU migrants in Britain, Mr Raab told the BBC's Andrew MarrShow:

"Well, I think that's a rather irresponsible thing to be coming from the other side.

"We ought to be trying to reassure citizens on the Continent and also here.

"There is obviously an attempt to try and ramp-up the pressure."

The government has sent mixed signals so far on the divorce bill.

Prime Minister Theresa May agreed in December to a financial settlement of £39bn that ministers said depended on agreeing future trade ties.

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Video:Barnier: Brexit White Paper 'constructive'

But cabinet members have since cast doubt on the position.

Chancellor Philip Hammond said shortly afterwards that he found it "inconceivable" Britain would not pay its bill, which he described as "not a credible scenario".

The UK is set to leave the EU on March 30 next year, but the two sides want to strike a divorce agreement by late October in order to give parliament enough time to endorse a deal.

Mr Raab said critics were mistaken to think Mrs May would not walk away without a deal if she had to.

"They're wrong. No bluffing," he told the Sunday Telegraph.

"The ball is now in the EU's court, and don't get me wrong, there will be plenty more negotiations, I've made that clear, but if they show us the same level of ambition, energy, pragmatism, this deal gets done in 12 weeks."

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Video:Boris attacks May's Brexit plan as 'miserable, permanent limbo'

Sky News political correspondent Lewis Goodall said Mr Raab has been keen to assert his authority in his new role.

"He wants to show his Brexiteer colleagues that he is still a Brexiteer at heart, he won't be messed around, he means business and that he's on top of his brief," he said.

"But it makes it no easier for Theresa May because Brussels is already getting impatient with all the shenanigans that have been going on in Westminster over the past 10 days, and his comments will do nothing to lighten the mood."